Fluctuating spo2. Does he need an x ray?

My husband had covid - the first rt pcr report had CT score of 20. His hrct score was 4/25. the second rt pcr report came positive still and had CT score of 25.45. This was on 28th April. Doc said he's fine, and can discontinue isolation. He did course of steroids (medrol) and ivermectin and antibiotics. His fever subsided with this medication. He is otherwise active and no fever in the last 15 days or so but his spo2 has been fluctuating for the last 2 days - in a min it is 87 and then if we remove it and put it again it is 95 or 94. But this is happening multiple times in the last 2-3 days hence don't think it's really an error in how he puts on the instrument on his finger. What should I do? Is another hrct advisable considering the risk associated with hrct? Does he need an x ray?